Absolute numbers of circulating basophils were measured in 55 atopic and 35 non-atopic individuals, using a flow cytometer for automated cell counting. They were significantly elevated in the atopic group (p < 0.001), but the total leucocyte count was not significantly different between the two groups. Eosinophil counts, which correlated with the number of basophils for both populations, were also significantly raised in the atopic group (p < 0.001). Individual variation in absolute basophil counts was not detected in sequential samples taken at daily intervals over 5 days, in 5 atopies and 4 non-atopies. In addition, no significant variation was detected in 6 atopies and 5 non-atopies over a period of up to 20 months.
The appearance in blood of rat mast cell protease II (RMCPII) and glycosaminoglycan (GAG) was examined in normal and Nippostrongylus brasiliensis-primed rats challenged intravenously with worm antigen. Systemic release of these two products occurred only in immune recipients of antigen; substantial levels of RMCPII were also present in the intestinal perfusates of these same rats and there was depletion of both RMCPII and mucosal mast cells (MMC) from the intestinal mucosa. Depletion of MMC was evident after staining for proteoglycan or for serine esterase and the mast cell counts with both histochemical techniques were highly correlated. Taken together, the results suggest that MMC are likely to be the principal source of secreted GAG and RMCPII.
Histamine and heparin, both free and cellular, were assayed in the nasal mucosa of 11 atopic and 15 nonatopic patients undergoing turbinectomy for chronic rhinitis. There was no significant difference between the free and cellular histamine levels of the atopic and nonatopic patients. There was also no significant difference between the free heparin levels of atopic and nonatopic patients. Mean cellular heparin was, however, significantly greater in the nonatopic group. This finding, together with the results of mast cell counting, suggests either that in atopic patients heparin stores are already depleted prior to turbinectomy, or that in nonatopic individuals nasal mast cells contain an excess of heparin in nonreleasable stores.
A study of absolute basophil counts and plasma levels of highly sulphated glycosaminoglycans in 30 peripheral blood samples from 21 patients with different leukaemias was performed. This revealed significantly raised levels of both plasma highly sulphated glycosaminoglycans and basophils in those patients with chronic myeloid leukaemia, as compared to those with other types of leukaemia and 35 normal controls. A strong correlation (r = 0.83) was observed between the levels of highly sulphated glycosaminoglycans and basophil counts in the group as a whole, supporting a direct relationship between the two. The elevated plasma levels of highly sulphated glycosaminoglycans may contribute to the bleeding tendency reported in some patients with chronic myeloid leukaemia.
A new assay for highly-sulphated glycosaminoglycans (GAGs) has been applied to the study of allergen (Dermatophagoides pteronyssinus)-induced release of GAG from human basophils. Highly-sulphated GAG, which was not heparin, was found only in basophil-containing cellular fractions of whole blood. Its release, like that of histamine, was Ca++-dependent. However, allergen-induced release of GAG from the basophils of atopic individuals exhibited a different time-course and dose-response from that of histamine, and may occur at least in part by a different mechanism.
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